Method and apparatus for recording digital data streams and management information

ABSTRACT

An optical disc and a method and apparatus for recording digital data streams and management information on the disc, are provided. The method includes recording a digital data stream including at least one predetermined-sized unit, each unit carrying header information and at least one packet, the header information being represented in at least one header entry, selectively appending an additional header entry based on whether a number of the at least one header entry corresponds to a number of the at least one packet, and recording an indication information that indicates whether or not the additional header entry is appended.

The present application is a continuation of U.S. patent applicationSer. No. 09/588,661 filed on Jun. 6, 2000 now U.S. Pat. No. 6,792,198,for which priority is claimed under 35 U.S.C. §120; and the presentapplication claims priority of Patent Application No. 99-25496 filed inRepublic of Korea on Jun. 29, 1999, under 35 U.S.C. §119. The entirecontents of application Ser. No. 09/588,661 are herein fullyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for recordingdigital data streams and their management information, which recorddigital data transport stream units such as application packets inpredetermined-sized sectors of a disk-type recording medium such as adigital versatile disk (referred as ‘DVD’ hereinafter) and which createand record the management information for the recorded transport streamunits.

2. Description of the Related Art

In the conventional analog television broadcast, video signals aretransmitted over the air or through cables after being AM or FMmodulated. With the recent advance of digital technologies such asdigital image compression or digital modulation/demodulation,standardization for digital television broadcast is in rapid progress.Based upon the Moving Picture Experts Group (MPEG) format, satellite andcable broadcast industry also moves towards the digital broadcast.

The digital broadcast offers several advantages that its analogcounterpart cannot provide. For example, the digital broadcast iscapable of providing services with far more improved video/audioquality, transmitting several different programs within a fixedbandwidth, and offering enhanced compatibility with digitalcommunication media or digital storage media.

In the digital broadcast, a plurality of programs encoded based upon theMPEG format are multiplexed into transport streams before transmitted.The transmitted transport streams are received by a set top box at thereceiver and demultiplexed into original programs. If a program ischosen among the demultiplexed programs, the chosen program is decodedby a decoder in the set top box and original audio and video signals areretrieved. The retrieved audio and video signals are then presented byan A/V output apparatus such as a TV.

FIG. 1 depicts a block diagram of a general digital data streamrecording system which includes a set top box 100, a communicationinterface such as IEEE-1394, and a streamer 200. The set top box 100receives transport streams, in which several programs are multiplexedand encoded by data encoders equipped in broadcasting stations, anddemultiplexes the received transport streams. After a data decoder 120in the set top box 100 decodes the transport streams corresponding to aprogram tuned by a tuning unit 110 under the control of a microcomputer140 to process a request from a user, it outputs the decoded transportstreams to an A/V device such as a TV set for presentation. The set topbox 100 may transmit the transport streams corresponding to a programchosen by a user to the streamer 200 through the IEEE-1394 interface sothat the transport streams corresponding to the chosen program arerecorded on a recording medium 230 such as a recordable DVD by thestreamer 200.

According to another request from a user, the set top box 100 mayreceive a recorded program reproduced from the recording medium 230 bythe streamer 200 through the IEEE-1394 communication interface, then thereceived program is presented on a TV set after being decoded by thedecoder 120 in the set top box 100.

Meanwhile, for recording received digital broadcast signals on arecording medium, it is necessary to develop schemes for writing thereceived digital data streams in sectors of fixed size, organizing themon the recording medium, and creating management information for therecorded digital streams. However, no international definite standardfor such schemes is available yet and thus various methods have beenproposed by relevant developers.

One of the proposed methods for recording digital data streams andcreating their management information will be explained with referenceto accompanying drawings.

FIG. 2 depicts the recording syntax for digital data streams. A streamobject (SOB), which is a recorded object created by a one-timerecording, includes a plurality of stream object units (SOBUs), and eachSOBU is recorded in a plurality of sectors. A single sector, whose sizeis 2048 bytes, can accept a plurality of application packets (APs) whosesize is 192 bytes and header information HDRS regarding the writtenapplication packets. The AP includes a 4-byte time stamp indicating thepacket arrival time and a 188-byte data packet.

Therefore, a 2048-byte sector may be filled with a header informationHDRS, several application packets (APs), and null data area ifnecessary, as shown in FIG. 2. The area filled with null data is calledas padding area and its size varies.

FIG. 3 shows the format of the application header information andapplication header extension information recorded in the headerinformation HDRS. The application header information containsinformation on a plurality of application packets recorded in its ownsector, and it comprises a field indicating a version of the headerformat, a field AP_NS indicating the number of application packets, andso on. The application header extension information, which is optional,requires 1 byte for each application packet recorded in its own sector,and it comprises fields AU_Start (Access Unit Start) and AU_End (AccessUnit End) indicating whether a packet belongs to starting and ending ofdata stream unit such as Infra-coded picture (referred as ‘I-Picture’hereinafter) data which is accessible at random, respectively; areserved field; and a field for copyright.

FIG. 4 shows a digital stream recording example by a recently proposedmethod for recording application packets in sectors. The method of FIG.4 divides an application packet into two parts if the remaining area ofa sector cannot accept a single application packet, and records thefirst part whose size is equal to the remaining area in the currentsector and the second part in the next sector. However, the remainingarea of the last sector belonging to a SOB is filled with null data.According to this method, a 2048-byte sector can be wholly used asrecording area except the last sector.

The recording example of FIG. 4 is explained in more detail to make therecently proposed method be understood better.

Since the remaining area of the sector M-2 is smaller than a single AP,a 192-byte AP is divided into 130-byte and 62-byte parts. The first130-byte part of the divided application packet is recorded as the lastrecorded packet AP_(M-2) #10 of the sector M-2 and the second 62-bytepart is recorded as the first recorded packet AP_(M-1) #1 of the sectorM-1. Then, 10-byte application header extension information for allapplication packets recorded in the sector M-2 including the partialapplication packet AP_(M-2) #10 is created and recorded in the headerarea HDRS of the sector M-2, and a value of 00001010b (10 in decimal) iswritten in the field AP_NS of the application header information.

Meanwhile, the sector M-1 contains the second 62-byte part as the firstrecorded packet AP_(M-1) #1 and 10 application packets AP_(M-1) #2 to#11 whose 192-byte data are all recorded in the sector M-1, 54-byte(=14+14+1+15) header information which is explained above referring toFIG. 3, and 11-byte application header extension information which isgenerated and recorded for 11 application packets, so that 2047 bytes(=62+1920+54+11) of the sector M-1 are used for data recording and 1byte remains in the sector M-1.

Accordingly, to use the whole 2048-byte sector, the next applicationpacket of 192 bytes should be divided into 1 byte and 191 bytes, and1-byte new application header extension information corresponding to theapplication packet whose the leading 1 byte is to be recorded in thesector M-1 should be generated and added in the sector M-1.

However, if 1-byte application header extension information is added inthe sector M-1, the sector becomes full and the next application packetto be divided should be recorded in the next sector M. In this case, theapplication packet recorded in the sector M corresponds to the headerextension information which is recorded in the different sector, andthere occurs a problem for recording the number of packets recorded inone sector. That is, if the number of the APs recorded in the sector M-1is written in the packet number field AP_NS, the written number is notequal to the number of header extension information in that sector, andif the number of header extension information is written in the fieldAP_NS, the written number is different from the number of the APsrecorded fully and partially in that sector.

To avoid such problems, the 1-byte header extension information shouldbe inevitably recorded in the next sector M. However, if the 1-byteheader extension information is recorded in the next sector M, thesector M-1 leaves 1 byte unused, which causes mismatch with theprovisional standard specification of stream recording that a sector isfully used without unwritten area if the sector is not the final one ofa SOB.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optical disc anda method and apparatus for recording digital data streams and theirmanagement information which record stream packets and managementinformation as maintaining one-to-one correspondence between streampackets and their management information in the same sector even if theremaining size of a sector becomes equal to the size of managementinformation for a single stream packet.

It is another object of the present invention to provide an optical discand a method and apparatus for recording digital data streams and theirmanagement information which can make the value of information forindicating the number of stream packets recorded in a sector coincidewith both numbers of management information and stream packets even ifthe remaining size of a sector becomes equal to the size of managementinformation for a single stream packet.

It is another object of the present invention to provide an optical discand a method and apparatus for recording a digital data stream, whichovercome the problems and limitations of the related art.

These and other objects of the present application will become morereadily apparent from the detailed description given hereinafter.However, it should be understood that the detailed description andspecific examples, while indicating preferred embodiments of theinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate the preferred embodiments ofthe invention, and together with the description, serve to explain theprinciples of the present invention.

In the drawings:

FIG. 1 is a block diagram of a general digital data stream recordingsystem;

FIG. 2 is a pictorial representation for the syntax of a recordeddigital data stream;

FIG. 3 is a pictorial representation for the format of generalapplication header information and application header extensioninformation;

FIG. 4 shows a conventional method of recording digital data streams insectors;

FIG. 5 is a pictorial representation for the syntax of applicationheader information and application header extension informationaccording to the present invention; and

FIG. 6 shows a recording example according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order that the invention may be fully understood, preferredembodiments thereof will now be described with reference to theaccompanying drawings.

FIG. 5 is a pictorial representation of application header informationand application header extension information according to the presentinvention. As described above referring to FIGS. 2 and 3, theapplication header information contains information on a plurality ofapplication packets recorded in its own sector, and it comprises a fieldindicating a version of the header format, a field AP_NS indicating thenumber of application packets, and so on. The application headerextension information, which is optional, requires 1 byte for eachapplication packet recorded in its own sector, and it comprises fieldsAU_Start (Access Unit Start) and AU_End (Access Unit End) indicatingwhether a corresponding packet is starting and ending of data streamunit such as I-Picture data which is accessible at random, respectively;a reserved field; a field for copyright; and a validity informationfield ‘Null_Flag’ indicating whether the application header extensioninformation is valid or not. All of 1-byte application header extensioninformation are recorded before the APs which are composed of 4-bytetime stamp and the 188-byte data packet individually.

The method embodying the present invention writes one-bit validity flagshowing the effectiveness of the application header extensioninformation in all the application header extension information, countsthe number of the application header extension information recorded inthe sector based upon of the values of the validity flags, and thenrecords the counted value in the field AP_NS. The determining andrecording operation for the validity information of the bit-sized fieldNull_Flag and the number information of the field AP-NS is now describedas it is implemented by the recording system shown in FIG. 1 as anexample. However, the present method can be applied to other suitablesystems.

FIG. 6 shows a recording example according to the present invention. Torecord digital streams and their management information like the formatshown in FIG. 6, the streamer 200 receives the transport stream packetsfrom the set top box 100 through the communication interface 210, addsarrival time to each transport stream packet, and then records themsequentially in a 2048-byte sector without unused area of null data.While recording, the stream recording unit 220 divides a singleapplication packet at the border of a sector and records two dividedpartial packets across two sectors through an internal optical pickup,and pads null data in the remaining area of the last sector belonging toa SOB.

Meanwhile, the control unit 250 is checking both sizes of a receiveddigital stream packet and the remaining area in a current sector of arecording medium 230 to record the packet in. As shown in FIG. 6, if 130bytes remain in the current sector to write the received packet in sothat the remaining area can not accept a full application packet, thecontrol unit 250 informs the stream recording unit 220 of the fact thatthe remaining size is small by 62 bytes to accept a packet. Then, thestream recording unit 220 divides the 192-byte application packet into130 bytes and 62 bytes based upon the informed fact, and records them asthe last recording packet AP_(M-2) #10 of the current sector M-2 and asthe first recording packet AP_(M-1) #1 of the next sector M-1,respectively.

For the application header extension information of the sector M-2, thecontrol unit 250 produces 10-byte application header extensioninformation for the 10 application packets including the partialapplication packet AP_(M-2) #10 (1 byte application header extensioninformation for each application packet) and controls the streamrecording unit 220 to record the produced 10-byte application headerextension information. Also, the control unit 250 makes a binary valueof 00001010b (10 in decimal) representing the number of the recorded APsbe written in the application packet number field AP_NS of theapplication header information.

However, the sector M-1 contains the first partial application packetAP_(M-1) #1 of 62 bytes, 10 application packets AP_(M-1) #2 to #11 offull size, 54-byte (=14+14+1+15) header information, and 11-byteapplication header extension information produced correspondingrespectively to the 11 application packets. According to these contentsbelonging to the sector M-1, the 2047 (=62+1920+54+11) bytes are to beused in the sector M-1, so that the sector M-1 has a remaining area.

If the size of the remaining area is the same as the size of headerextension information for a single AP, that is, if the size of theremaining area is 1 byte as in the sector M-1, the control unit 250produces an invalid header data according to the following procedure andcontrols the stream recording unit 220 to record the invalid headerdata.

The control unit 250 should divide the received 192-byte applicationpacket into 1 byte and 191 bytes to use the whole area of the 2048-bytesector M-1. However, if the divided partial AP of 1 byte is to berecorded in the sector M-1, a new one-byte application header extensioninformation corresponding the 1-byte partial AP should be also added inthe sector M-1, so that the sector M-1 lacks one byte.

Accordingly, the control unit 250 produces a 1-byte invalid header dataand controls the stream recording unit 220 to record the produced 1-byteinvalid header data in the sector M-1 to fill up the 2048 bytes,therefore, the received 192-byte application packet is recorded in thenext sector M without being divided.

The invalid header data recorded in sector M-1 is application headerextension information, however, it has not correspondence with a AP.Thus, the invalid header data should be distinguished from normalapplication header extension information. To indicate the validity ofapplication header extension information, the value 0b or 1b is writtenin the validity information bit Null_Flag which is one bit of the headerextension information field, wherein the value 1b represents thatapplication header extension information is not corresponding to a AP.Therefore, in the sector M-1, the application header extensioninformation with Null_Flag=1b can be differentiated from the 11application header extension information with Null_Flag=0b producedcorresponding to the effective 11 application packets AP_(M-1) #1 andAP_(M-1) #2 to #11.

Accordingly, although 11 application packets and 12 application headerextension information are recorded in the sector M-1, the lastapplication header extension information recorded only for fully usingof a sector can be discriminated based on the value of the bitNull_Flag. After counting the effective application header extensioninformation whose the validity bit is 0b, the value of 00001011b (11 indecimal) representing the number of the effective 11 application headerextension information or the number of the 11 application packetsrecorded in the sector M-1 is recorded in the field AP_NS to indicatethe number of APs for the sector M-1.

The method and apparatus for recording digital data stream andmanagement information in accordance with the present invention recordinvalid header data distinguishable from the normal application headerextension information in front of the application packets as explainedin detail hereinbefore, if the remaining area of a sector is equal toapplication header extension information in size. Accordingly, thismethod of the present invention records effective application headerextension information whose the number coincides with the number of APsrecorded in the same sector, so that prevents mismatch between the valueto be written in the field AP_NS to indicate the number of applicationpackets and either of the number of the recorded APs and the number ofapplication header extension information. Moreover, this method does notleave any unused area to pad null data at the border of a sector, and,thereby satisfies the standard specification for a digital data streamrecording medium.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

1. A method of electronically recording a data stream onto a datarecording medium, comprising: recording a digital data stream includingat least one predetermined-sized unit, each predetermined-sized unitcarrying header information and a plurality of packets, the headerinformation being represented in a plurality of header entriescorresponding to the plurality of packets; selectively appending anadditional header entry based on whether a total number of the pluralityof header entries corresponds to a total number of the plurality ofpackets recorded in each predetermined-sized unit; and recordingindication information that indicates whether or not the additionalheader entry is appended.
 2. The method of claim 1, wherein in theselectively appending step, the additional header entry is appended ifthe total number of the plurality of header entries does not correspondto the total number of the plurality of packets.
 3. The method of claim2, wherein in the selectively appending step, the additional headerentry is appended only if the total number of the plurality of headerentries is not the same as the total number of the plurality of packets.4. The method of claim 1, wherein the plurality of header entriescarries management information for managing the plurality of packets. 5.The method of claim 1, wherein each of the plurality of header entriescorresponds to one of the plurality of packets.
 6. The method of claim1, wherein the appending step comprises: appending the additional headerentry to the plurality of header entries.
 7. The method of claim 1,wherein the data recording medium is an optical disc.
 8. A method ofelectronically reproducing a data stream from a data storage medium,comprising: reading a digital data stream including at least onepredetermined-sized unit, each predetermined-sized unit carrying headerinformation and a plurality of packets, the header information beingrepresented in a plurality of header entries, wherein there isone-to-one correspondence between the plurality of header entries andthe plurality of packets; identifying indication information thatindicates whether or not an additional header entry is present; andreproducing the header information from the plurality of header entriesby excluding the additional header entry if the indication informationindicates that the additional header entry is present, wherein theadditional header entry is present depending on whether or not a totalnumber of the plurality of header entries corresponds to a total numberof the plurality of packets in each predetermined-sized unit.
 9. Themethod of claim 8, wherein the additional header entry is present if thetotal number of the plurality of header entries is different from thetotal number of the plurality of packets.
 10. The method of claim 8,wherein the plurality of header entries carries management informationfor managing the plurality of packets.
 11. The method of claim 8,wherein the data storage medium is an optical disc.
 12. A non-transitoryrecording medium for recording a data stream, comprising: a recordinglayer; a digital data stream recorded on the recording layer andincluding at least one predetermined-sized unit, eachpredetermined-sized unit carrying header information and a plurality ofpackets, the header information being represented in a plurality ofheader entries; an additional header entry selectively appended in thedigital data stream based on whether a total number of the plurality ofheader entries corresponds to a total number of the plurality of packetsin each predetermined-sized unit; and indication information recorded onthe recording layer, the indication information indicating whether ornot the additional header entry is appended.
 13. The non-transitoryrecording medium of claim 12, wherein the additional header entry isappended if the total number of the plurality of header entries does notcorrespond to the total number of the plurality of packets.
 14. Thenon-transitory recording medium of claim 13, wherein the additionalheader entry is appended only if the total number of the plurality ofheader entries is not the same as the total number of the plurality ofpackets.
 15. The non-transitory recording medium of claim 12, whereinthe plurality of header entries carries management information formanaging the plurality of packets.
 16. The non-transitory recordingmedium of claim 12, wherein each of the plurality of header entriescorresponds to one of the plurality of packets.
 17. The non-transitoryrecording medium of claim 12, wherein the additional header entry isappended to the plurality of header entries of the digital data stream.18. The non-transitory recording medium of claim 12, wherein therecording medium is an optical disc.
 19. A non-transitory recordingmedium for recording a data stream, comprising: a recording layer; adigital data stream recorded on the recording layer and including atleast one predetermined-sized unit, each predetermined-sized unitcarrying header information and a plurality of packets, the headerinformation being represented in a plurality of header entries, whereinthere is one-to-one correspondence between the plurality of headerentries and the plurality of packets; and an invalid header entryselectively recorded on the recording layer depending on whether or nota total number of the plurality of header entries corresponds to a totalnumber of the plurality of packets in each predetermined-sized unit. 20.The non-transitory recording medium of claim 19, wherein the invalidheader entry is created and appended if the total number of theplurality of header entries is different from the total number of theplurality of packets.
 21. The non-transitory recording medium of claim19, further comprising: indication information recorded on the recordinglayer, the indication information indicating whether or not the invalidheader entry is present.
 22. The non-transitory recording medium ofclaim 19, wherein the plurality of header entries carries managementinformation for managing the plurality of packets.
 23. Thenon-transitory recording medium of claim 19, wherein the recordingmedium is an optical disc.
 24. An apparatus for recording a data stream,comprising: a recorder configured to record a digital data streamincluding at least one predetermined-sized unit, eachpredetermined-sized unit carrying header information and a plurality ofpackets, the header information being represented in a plurality ofheader entries; and a controller configured to selectively append anadditional header entry based on whether a total number of the pluralityof header entries corresponds to a total number of the plurality ofpackets in each predetermined-sized unit, wherein the controller isconfigured to control the recorder to record indication information thatindicates whether or not the additional header entry is appended.
 25. Anapparatus for recording a data stream, comprising: a reproducerconfigured to read a digital data stream including at least onepredetermined-sized unit, each predetermined-sized unit carrying headerinformation and a plurality of packets, the header information beingrepresented in a plurality of header entries, wherein there isone-to-one correspondence between the plurality of header entries andthe plurality of packets; and a controller configured to identifyindication information that indicates whether or not an additionalheader entry is present and to reproduce the header information from theplurality of header entries excluding the additional header entry if theindication information indicates that the additional header entry ispresent, wherein the additional header entry is present depending onwhether or not a total number of the plurality of header entriescorresponds to a total number of the plurality of packets in eachpredetermined-sized unit.